I mentioned previously that I was interested in the many different words for shield in Homer. Propertius II found an article which is, in fact, the first thing that pops up on Google when one searches for "Homeric Sheild." The article is from 1913 and is probably out of date, but I found it quite intersting. In the article "Notes on the Homeric Shield" (JSTOR), Tayler argues that there are two main types of shield in Homer: ἀσπίς and σάκος. Almost to a person, the Trojans use ἀσπις, which Tayler posits are large Minoan-style hide covered shields, while the Achians use a combination of ἀσπίς and σάκος all though most of them prefer the smaller metal σάκος. Sometimes, the stronger of the heroes use ἀσπίς with large metal designs (usually circles). Making the large ἀσπίς entirely out of metal would be too heavy.
The "note" was short and intriguing. Tayler mentions that he is not actually an archaeologist and he is basing his evidence primarily on the literary distribution of the two words throughout the text. If anyone has more recent information on this, I would love to read it.